In a holder for minicomputers or similar apparatus, including a planar body, which is inclined in a normal operating position, and clamping jaws arranged at opposite sides for engaging therebetween an apparatus placed onto the planar body, the planar body has at least at one end thereof a guide groove with stop fingers slidably supported in the guide groove so as to extend therefrom upwardly above the surface of the planar body to prevent any apparatus from sliding off the planar body, the stop fingers being position adjustable along the guide slot for accommodating plug or connections provided at the bottom end of the apparatus.